Can and how do you lose parental rights?

My stepson does not see or pay child support for his son,But I have taken care of him for 3yrs everyday for 12 to 14hrs a day and alot of overnights.This little boy means the world to me and my husband! But the mother has a new boyfriend and he will not let us see him anymore,we found out he cries all the time to see us he was very very close to me.She said her new boyfriend was going to adopt our grandson and my stepson was losing his parental rights and will not be his grandparents anymore. thank you